Starting at about 1:22 in the trailer, an announcement starts broadcasting on repeat. It is presumably coming from the truck we see a couple of seconds later. What is this announcement?
This seems to be the beginning of the evacuation announcement which you can also listen to, repeating the first two words, which sound like a repetion of внимание (engl. attention) - there is an audio clip, too.
So, in the trailer, it's just
The original announcement (April 27, 1986) then went on
For the attention of the residents of Pripyat! The City Council informs you that due to the accident at Chernobyl Power Station in the city of Pripyat the radioactive conditions in the vicinity are deteriorating. [...] Nevertheless, with the view to keep people as safe and healthy as possible, the children being top priority, we need to temporarily evacuate the citizens in the nearest towns of Kiev region. [...]
Then the announcement
FOR THE ATTENTION OF THE RESIDENTS OF PRIPYAT. [...]
as already quoted above.